When most people think of metaphor, they cast their minds back to school and remember examples from poetry and drama, such as Shakespeare’s “Juliet is the sun”. This is unsurprising; metaphor is usually described as a literary phenomenon used to create arresting images in the mind of the reader. However, linguists would argue that metaphor is far more pervasive within our language and indeed within thought itself.

Metaphor is fundamental to the ways in which we conceptualise and articulate even seemingly basic concepts. We talk about the mind as if it were a container for ideas, which can be placed in there or taken out and passed to others. We talk about our lives as if they were journeys with milestones, obstacles and end points. In fact it is difficult to talk about abstract ideas at all without using vocabulary from another area. When we talk about ‘a healthy economy’ or ‘a clear argument’ we are using expressions that imply the mapping of one domain of experience (e.g. medicine, sight) onto another (e.g. finance, perception). When we describe an argument in terms of warfare or destruction (‘he demolished my case’), we may be saying something about the society we live in. Metaphor, then, might have an effect on the ways in which people understand the world around them: if immigration is presented in terms of a flow of water by the media (e.g. as a wave or as a flood) then this may predispose people to think about this issue in a particular way.

This theory of conceptual metaphor was popularised by Lakoff and Johnson (1980) in the book Metaphors We Live By and has been hugely influential ever since. What has been missing from this field so far is an overall picture of metaphor within a language. This is exactly what the Metaphor Map is designed to show. Using the data behind the Historical Thesaurus of the Oxford English Dictionary, we have ‘mapped’ all areas of meaning which share vocabulary and used these to discover where metaphorical connections exist in English. For an introduction to the mapping process, please see this blog post. The Metaphor Map gives an overview of metaphor over the course of the last 1300 years of English, from the seventh century to the present day. If we accept that metaphorical connections can indicate how people mentally structure their world within a particular society, then the results can be seen as very intriguing indeed.

Key questions about metaphor remain to be answered; for example, how did metaphors arise? Which domains of experience are most prominent in metaphorical expressions? How have the metaphors available in English developed over the centuries in response to social changes? With the completion of the Historical Thesaurus, we could begin to address these questions comprehensively and in detail for the first time through the Metaphor Map of English. We now have the opportunity to track how metaphorical ways of thinking and expressing ourselves have changed over more than a millennium.

Almost half a century in the making, the Historical Thesaurus is the first source in the world to offer a comprehensive semantic classification of the words forming the written record of a language. In the case of English, this record covers thirteen centuries of change and development, in metaphor as in other areas. We have used the Historical Thesaurus evidence base to investigate how the language of one domain of experience (e.g. medicine) contributes to others (e.g. finance). In this annotated ‘Metaphor Map’ we have systematically identified instances where words extend their meanings from one domain into another. So we can track how words from light, for example, are used in other areas of the language such as intelligence and knowledge, while words from darkness are used for lack of intelligence and lack of knowledge. By using the Metaphor Map as a basis for research, we may begin to see innovations in metaphorical thinking at particular periods in history and in particular areas of experience.

[Earlier versions of parts of this post can be found at http://www.keblog.arts.gla.ac.uk/2014/02/11/mapping-metaphor/ and http://www.gla.ac.uk/schools/critical/research/fundedresearchprojects/metaphor/]